Service dogs are more stress-resistant than other animals, but they are also susceptible to stress factors, which can lead to changes in their bodies and their ability to perform their tasks. In this regard, the aim of the study was to investigate the effect of excessive stress factors in the form of powerful ballistic shelling of the territory on the organism of service dogs at the physiological and behavioural levels and to identify markers of stress disorders in these animals. Visual examinations, morphological, biochemical, computational and statistical methods were used to determine the main criteria that help differentiate stress markers in service dogs. It was found that physiological criteria, such as heart rate and breathing rate, and behavioural reactions change even before the shelling due to the hypersensitive hearing and increased sensitivity to vibrations in service dogs, and quickly return to normal within an hour after the stressor has ceased. At the same time, the enhanced response to stressors does not affect the ability of service dogs to perform their work tasks. It was also found that service dogs aged 4-5 years are more resistant to stress, as confirmed by the absence of significant changes in serum cortisol levels during the study. Service dogs aged 1-1.5 years are more susceptible to stress factors, as evidenced by a 6.68-fold increase in cortisol levels (P < 0.001) during the first stress factor and a 1.69-fold increase (P < 0.001) after repeated exposure. Studying the condition of service dogs under stress factors will allow the development of effective methods for diagnosing and preventing stress in animals and maintaining their working capacity. The results of the study can be useful for veterinarians in developing diagnostic criteria and methods for monitoring and correcting changes in the body of animals caused by stress
acute stress; chronic stress; diagnosis; behavioural changes; haematological parameters; cortisol
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